ALACOQUE, or Al Coq, MARGUERITE MARIE (1647-1690), French nun and mystic, was born at Lauthecourt, a village in the diocese of Autun, on the 22nd of July 1647. She would seem to have been from the first of a morbid and unhealthy temperament, and before the age of thirteen was the subject of a paralytic seizure. Having been cured of this, as she believed, by the intercession of the Holy Virgin, she changed her name to Marie and vowed to devote her life to her service. In May 1671 she entered the Visitation convent at Paray-le-Monial, in the diocese of Autun, and took the final vows in November 1672. Though her reading was confined to the lives of the saints, she taught in the school kept by the nuns for the girls of the neighbourhood, to whom she endeared herself by her kindly disposition. The appalling austerities, however, to which she was allowed to subject herself quickly affected her mental and bodily health. Hallucinations, to which she had been always subject, became more and more frequent. She conceived herself to be specially favoured by Christ, who appeared to her in the most extravagant forms. At last, by dint of fasting and lacerating her flesh, she succeeded in reducing herself to such a state of ecstatic suffering that she believed herself to be undergoing in her own person the Passion of the Lord. Her reward was the, supreme vision in which Christ revealed to her His heart burning with divine love, and even, so she affirmed, exchanged it with hers, at the same time bidding her establish, on the Friday following, the feast of Corpus Christi, a festival in honour of His Sacred Heart. It was not till ten years later, in 1685, that the festival was first celebrated at Paray, and not till after the death of Marguerite, on the 17th of October 1690, that the cult of the Sacred Heart, fostered by the Jesuits and the subject of violent controversies within the church, spread throughout France and Christendom. (See Sacred Heart.)

Marguerite Alacoque was beatified by Pius IX. in 1864. Her short devotional writing, La Dévotion au Sacré-Cœur de Jésus, was published by J. Croiset in 1698, and is now very popular among Roman Catholics.